Antifungal nail coat and method of use

ABSTRACT

Antifungal nail coat compositions containing an allylamine, an N,N-di(C 1 -C 8 ) alkylamino substituted, (C 4 -C 18 ) alkyl (C 2 -C 18 ) carboxylic ester or a pharmaceutically acceptable acid addition salt thereof, a hydrophilic polymer, and a pharmaceutically acceptable, volatile organic carrier are disclosed. The composition provides a substantially water-soluble, fungicidal coating upon contact with a fungally susceptible or infected nail.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.10/514,190, filed Nov. 10, 2004, now U.S. Pat. No. 7,462,362, which is aU.S. National Stage of international application No. PCT/US2004/008618,filed Mar. 22, 2004, which application claims benefit of U.S.Provisional Patent Application No. 60/456,684, filed Mar. 21, 2003,incorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

This invention relates to topical antifungal compositions useful forameliorating or preventing onychomycoses of the toenails or fingernails,as well as adjacent skin. More particularly, the invention relates to adual action antifungal nail coat composition and the method for applyingthe antifungal composition to a fungally susceptible or infected nailand/or adjacent skin.

BACKGROUND OF THE INVENTION

Superficial fungal infections of skin, hair, nails, or mucous membranes,are still very common among all populations. In particular,onychomycosis is a fungal infection of the nails. The onychomycosis arefrequent, involving up to about 15% of persons between the ages of 40and 60 years. Some estimates suggest that onychomycosis affects about 6to about 13% of the North American population, with an estimated 4.9 to12.3 million people being affected in the United States. In Europeanpopulations, the estimated overall prevalence of onychomycosis is in therange of about 3 to about 10%.

Delivery of antifungal agents through the nail into the nail bed andsurrounding skin has been minimally effective for the treatment ofonychomycosis (infections of the fingernails, toenails, and immediateadjacent surrounding skin) in the form of a nail lacquers, primarilybecause the film forming water-insoluble polymers used limit thediffusion of the drug from the dried film into the nail and skin, andbecause previous nail lacquer compositions do not contain the optimumbalance of permeation enhancement to deliver the drug to both the nailand surrounding skin in an amount sufficient for optimal antifungalactivity.

Fungal infection of the nails, commonly referred to as onychomycosis, ismost frequently caused by dermatophytes, but can also be caused by moldsand Candida sp. Onychomycosis is predominantly present in toenailsrather than fingernails, in males, and in the elderly. Onychomycosis ismost commonly caused by Trichophyton rubrum (T. rubrum), Trichophytonmentagrophytes (T. mentagrophytes), and Epidermophyton floccusum (E.floccusum). Onychomycosis due to nondermatophytes is usually caused byCandida species, such as Candida albicans, and is more likely to causeinvasive nail disease in fingernails than in toenails of immunocompetentindividuals.

Onychomycosis has medical significance especially in individuals havingcertain diseases, such as diabetes and others where the individual isimmunocompromised. Also onychomycosis can have a substantial undesirableeffect on daily living activities, such as ambulation, and spontaneousremission is rare. The current treatments of onychomycosis include oraladministration of antifungal agents, such as itraconazole (distributedunder the tradename, SPORONOX®, by Ortho Biotech Products L.P.), andterbinafine (distributed under the tradename, LAMISIL®, by NovartisPharmaceuticals Corporation). While itraconazole and terbinafinehydrochloride offer significant cure rates, shorter treatment regimensand lower levels of adverse events compared to the imidazoles (e.g.,ketoconazole), clinically significant drug interactions can occur andthe therapeutic period requires at least a few months. Thus, there is anongoing need and desire for a non-oral management of onychomycosis.

One attempt has been made employing the antifungal agent, ciclopiroxdistributed commercially under the trade name PENLAC™ Nail Lacquer byDermik Laboratories, Inc.), as an 8% topical solution containing awater-insoluble, film-forming polymer, and is described in U.S. Pat. No.4,957,730 to Bohn, et al. Another antifungal nail lacquer compositionsutilizing a water-insoluble film forming polymer is described in U.S.Pat. No. 6,495,124 by Samour. Yet another nail lacquer formulationcontains 5% amorolfine, a morpholine derivative, and is manufactured byRoche Laboratories under the trade name LOCERYL™. However,water-insoluble film-forming polymers, such as used in conventional naillacquer compositions are fast drying (less than one minute) solution ofwater-insoluble polymers and, if brushed onto the skin area surroundingthe nail, tend to irritate the skin area. Additionally, suchtraditional, water-insoluble, fast drying, film-forming polymers producehigh viscosity nail lacquer compositions and thus limit the mobility andtime for active exchange of the antifungal agent between the film andthe nail plate resulting in loss of treatment efficacy. In someinstances, the nail lacquers are suitable only for treatment of mildonychomycosis without nail matrix involvement, and systemic treatment isstill required for severe onychomycosis involving the nail bed.

An attempt employing azole derivatives at 0.5-1% concentration appliedfrom a composition containing water-insoluble fatty components,solubilizers and a quick drying, water-soluble, polyvinylpyrrolidone, orvinylacetate copolymers and terpolymers thereof, is described inCanadian Patent No. 1,175,355 and European Patent No. 055,397.

The present dual action antifungal topical nail coat compositions andmethods provide a fungicidal regimen suitable for the treatment ofonychomycosis of varying severities in mammals in need of suchtreatment.

SUMMARY OF THE INVENTION

A dual action antifungal nail coat composition containing an antifungalagent for ameliorating or preventing fungal infections of nails andsurrounding skin, and onychomycosis in particular, is disclosed. Thepresent composition delivers the active ingredient both through the nailplate as well as through the surrounding skin tissue. Also disclosed aremethods for topically applying the dual action antifungal nail coatcomposition to a fungally-susceptible or infected nail. Thebioavailability of the antifungal agent is optimized by the practice ofthe present invention.

The antifungal nail coat compositions can be formulated as “one-coat”type and “two-coat” type compositions.

A preferred one-coat type antifungal nail coat composition embodimentcomprises:

-   -   an effective fungicidal amount of an antifungal agent;    -   a permeation enhancing amount of a substantially non-volatile,        permeation enhancer selected from the group consisting of an        N,N-di(C₁-C₈) alkylamino substituted, (C₄-C₁₈) alkyl (C₂-C₁₈)        carboxylic ester or pharmaceutically acceptable acid addition        salt thereof, a pharmaceutically acceptable alcohol, and        mixtures thereof;    -   a film-forming amount of a hydrophilic polymer; and    -   a pharmaceutically acceptable, volatile organic carrier.

In a one-coat type, dual action antifungal nail coat composition, theorganic carrier preferably assists in distributing the drug, i.e., theantifungal agent, substantially uniformly on contact of the nail coatcomposition with a fungally susceptible or infected nail and or adjacentskin and volatilizes, within about one to five minutes followingapplication to provide a substantially water-soluble, fungicidal filmcoating on the nail and adjacent skin tissue containing the drug and oneor more substantially non-volatile penetration enhancer for on-goingamelioration or prevention of fungal infection.

Another preferred dual action antifungal nail coat composition is atwo-coat type composition comprising:

-   -   a first antifungal nail coat composition for providing an        antifungal primer coat, comprising an effective fungicidal        amount of antifungal agent dispersed in a pharmaceutically        acceptable, volatile organic carrier;    -   a second antifungal nail coat composition for providing an        antifungal film coat, comprising a film-forming amount of        hydrophilic polymer, an effective fungical amount of antifungal        agent, and a pharmaceutically acceptable, volatile organic        carrier, and    -   wherein either one of the first or second antifungal nail coat        composition optionally includes a substantially non-volatile        permeation enhancer.

In a two-coat type, dual action composition, the antifungal agent isquickly released from the first antifungal nail coat composition to afungally-susceptible or infected nail on contact therewith to provide afungicidal primer coat. The second antifungal nail coat compositionprovides a fungicidal film coat over the foregoing fungicidalprimer-coated nail on subsequent contact therewith. The fungicidal filmcoat provides a depot for additional antifungal agent which can bereleased over an extended time period and provides a protective nailbarrier to maintain sustained release of antifungal agent from theprimer coat to the nail to optimize the topical bioavailability ofantifungal agent, and to minimize further accessibility of fungal sporesfrom the environment to the infected nail.

The antifungal agent is preferably selected from the group consisting ofallylamine and azole antifungals. The allylamine antimycoticterbinafine, usually as terbinafine hydrochloride, is particularlypreferred. The azole antifungals include azoles, imidazoles, as well astriazoles.

The hydrophilic polymer may be a film-forming polymer comprising avinylpyrrolidone monomer unit, including homopolymers (such as,polyvinylpyrrolidone), copolymers, and complexes thereof, a gum, aresin, or the like. Preferably, the hydrophilic polymer ispolyvinylpyrrolidone (PVP).

The volatile organic carrier preferably is a pharmaceutically acceptablealiphatic alkanol having 2 to about 5 carbon atoms, and more preferablyis ethanol.

Particularly preferred substantially non-volatile permeation enhancersare dodecyl-2-(N,N-dimethylamino) isopropionate (DDAIP), benzyl alcoholand combinations thereof.

The dual action antifungal nail coat compositions of this invention caninclude one or more penetration enhancers in an amount effective toachieve an antifungal concentration of the antifungal drug in the nailand surrounding skin, as well as an auxiliary anti-infective, such as anantibacterial agent, an antiseptic agent, and the like, to augment theefficacy of the treatment.

Fungal infection of a toenail or fingernail may be ameliorated orprevented by fungicidal regimens in which the disclosed dual actionantifungal topical nail coat compositions are applied in the form ofeither a one-coat type or a two-coat type by the methods describedherein. The methods of this invention are preferably performed at leastonce a day for as long as needed to ameliorate or prevent fungalinfection.

The practice of this invention using dual action antifungal nail coatcompositions is desired for increasing the topical bioavailability of anantifungal drug, especially in the treatment of onychomycoses of thetoenails or fingernails. Beneficially, the dual action antifungal nailcoat composition can shorten the total therapeutic period, avoid oreliminate adverse systemic events usually associated with oraltherapies, and improve clinical efficacy.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings,

FIG. 1 is a graphical representation of terbinafine uptake by human nailclippings from a selected individual expressed as the concentration ofterbinafine remaining in a terbinafine source solution as a function oftime, wherein Solution A was 10 weight percent terbinafine hydrochloridein anhydrous ethanol, Solution B was 10 weight percent terbinafinehydrochloride in anhydrous ethanol plus 10 weight percent ofpolyvinylpyrrolidone (K-30), Solution C was 10 weight percentterbinafine hydrochloride in anhydrous ethanol plus 0.5 weight percentDDAIP.HCl, and Solution D was 10 weight percent terbinafinehydrochloride in anhydrous ethanol plus 1 weight percent DDAIP.HCl;

FIG. 2 is a graphical representation of terbinafine release from thehuman nail clippings of the selected individual of FIG. 1 expressed as acalculated amount of terbinafine hydrochloride remaining in the nailclippings as a function of time, wherein Sample A was previously treatedwith Solution A, Sample B was previously treated with Solution B, SampleC was previously treated with Solution C, and Sample D was previouslytreated with Solution D;

FIG. 3 is a graphical representation of the calculated amount ofterbinafine hydrochloride retained in human nail clippings as a functionof DDAIP.HCl concentration in a solution of terbinafine hydrochloride inanhydrous ethanol; and

FIG. 4 is a graphical representation of the permeation of terbinafinehydrochloride in human nail clippings as a function of time from a 10weight percent solution of terbinafine hydrochloride in anhydrousethanol and from a 10 weight percent solution of terbinafinehydrochloride in anhydrous ethanol and also containing 0.5 weightpercent DDAIP.HCl.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The term “dual action” as applied to antifungal nail coat compositionsof this invention means that the nail coat composition provides awater-soluble, fungicidal film coating that contains the antifungal drugon the nail and adjacent skin tissue, and a substantially non-volatilepenetration enhancer that promotes the penetration of antifungal druginto the nail as well as surrounding skin tissue.

There is no particular limitation on the antifungal agents useful forthe dual action antifungal nail coat compositions of this invention, aslong as the antifungal agent is effective against fungi known to causeinfections of the toenails or fingernails, as well as surrounding skin,and onychomycosis, in particular. A listing of antifungal agents,without limitation thereto, may be found, for example, in the ThirteenthEdition of The Merck Index (2001) under the headings “Antifungal(Antibiotic)” and “Antifungal (Synthetic)” in the Therapeutic Categoryand Biological Activity Index section incorporated herein by reference.

Suitable antifungal agents include, for example allylamines, such asterbinafine, naftifine and butenafine; and azoles, such as imidadazolesand triazoles, and the like. Imidazoles include ketoconazole,bifonazole, butoconazole, chlordantoin, chlormidazole, cloconazole,clotrimazole, econazole, enilconazole, fenticonazole, flutrimazole,isoconazole, lanoconazole, miconazole, neticonazole, omoconazole,oxiconazole nitrate, sertaconazole, sulconazole, and tioconazole.Triazoles include fluconazole, itraconazole, posaconazole,saperconazole, terconazole and voriconazole. Particularly preferred isthe allylamine, terbinafine; the imidazole, ketoconazole; and thetriazoles fluconazole, and itraconazole.

This invention as described is particularly applicable to terbinafineand its acid addition salts without limitation thereto. The practice ofthis invention using terbinafine is desired since increasing the topicalbioavailability of this antifungal drug is useful in the treatment ofonychomycosis of the toenails or fingernails. Beneficially, the dualaction antifungal nail coat composition can shorten the totaltherapeutic period, avoid and eliminate systemic adverse events, andimprove clinical efficacy because it is applied to the target site ofthe fungal infection.

Terbinafine is designated chemically as(E)-N-(6,6-dimethyl-2-hepten-4-ynyl)-N-methyl-1-naphthalene methanamineand has the following structural formula:

The term “terbinafine” as used herein includes the free base form ofthis compound as well as chemotherapeutically acceptable acid additionsalts thereof. Suitable salt forms include hydrochloride, hydrogenfumarate or naphthaline-1,5-disulphonate. For purposes of the presentinvention, the inorganic acid salt, terbinafine hydrochloride, isparticularly preferred. Terbinafine hydrochloride is a syntheticantimycotic allylamine related to naftifine, and is the activeingredient (equivalent to 250 mg base) of a commercial antifungalmedication sold under the name LAMISIL® (Novartis PharmaceuticalsCorporation) formulated in tablets for oral administration. Thepreparation of propenylamines, which includes terbinafine, is describedin U.S. Pat. No. 4,755,534 and topical application dosage forms forpharmaceutical use reported therein are ointments or creams atconcentrations of from 0.05 to 5, and 0.1 to 1 weight percent, inparticular.

The present invention permits optimization of the clinical andmycological efficacy of terbinafine in a comprehensive managementprogram based on topical treatment for ameliorating various severitiesof onychomycosis of fingernails and toenails as well as the surroundingskin where dermatophytes harbor. The comprehensive management programpreferably comprises a daily regimen of topically applying a dual actionantifungal nail coat composition as described below to ameliorate orprevent onychomycosis, and preferably includes removal of the unattachedinfected nail at least monthly.

The dual action antifungal nail coat composition embodiments can beformulated as a “one-coat” type composition or as a “two-coat” typecomposition. The term “one-coat type composition,” as used herein, meansthat the antifungal nail coat composition contains a volatile carrier toassist in initially distributing the drug on contact with the nail andthe surrounding skin, and then volatilize relatively quickly, (i.e.,within a period in the range of about 0.5 to about 10 minutes), so thatthe hydrophilic polymer and substantially non-volatile permeationenhancer can provide a substantially uniform fungicidal film coat on thenail and adjacent skin tissue as a depot for the drug to provide ongoingamelioration or fungicidal prevention efficacy. The fungicidal film coatthus remains in contact with the nail until the nail coat is removed,such as by water rinsing or bathing. In this manner, an undesirablebuild-up of polymeric carrier films encountered by prior art antifungalnail lacquers is avoided.

A one-coat type composition is preferably applied at least once daily,as needed, and can be re-applied with or without an intervening waterrinse.

In a one-coat type of antifungal nail composition, the amount ofantifungal agent present usually is in the range of about 0.1 to about20 weight percent, preferably in the range of about 0.5 to about 15weight percent, and most preferably in the range of about 1 to about 5weight percent.

The term “two-coat type antifungal nail composition,” as used herein,refers to a two-part, dual action antifungal nail coat compositionformulation, each of which is sequentially applied, at least once daily.Thus a two-coat type antifungal nail composition comprises: a firstantifungal nail coat composition, which provides a fungicidal primercoat for relatively quick, substantially uniform, permeation ofterbinafine into, across and onto the nail plate and the adjacent tissuearea, and a second antifungal nail coat composition which subsequentlyprovides a substantially uniform film depot coat over the fungicidalprimer-coated nail to act as a nail-protective barrier and a depot foradditional terbinafine which can be gradually released. Thus, the secondantifungal nail composition is applied directly to the primer-coatednail with no intervening water rinse.

In a two-coat type embodiment of an antifungal nail coat composition,the amount of antifungal agent present in the respective first andsecond antifungal nail coat compositions can vary, but preferably, theweight ratio of antifungal agent in the second nail coat compositionrelative to that in the first nail coat composition is less than aboutone. Depending on the severity of the infection, the amount ofantifungal agent in the first antifungal nail coat composition can varyin the range of about 0.1 to about 20 percent by weight of the totalcomposition, and the amount of antifungal agent in the second nail coatcomposition may be an amount in the range of about 0.1 to about 15percent by weight of the total composition.

A preferred first antifungal nail coat composition embodiment for atwo-coat type composition is a substantially clear, colorless solutioncontaining terbinafine at a concentration in the range of about 0.5 toabout 20 weight percent, more preferably about 10 weight percentdissolved in a volatile, pharmaceutically acceptable carrier. Thevolatile carrier preferably is an alkanol having 2 to about 5 carbonatoms, such as ethanol, propanol, isopropanol, butanol, isobutanol, andthe like. Ethanol is particularly preferred. The volatile carrier canalso serve as a penetration enhancer.

A particularly preferred first antifungal nail coat compositioncomprises about 10 percent terbinafine in ethanol on a weight/weightbasis. Preferably, the first antifungal nail coat composition wicksalong the capillary system of and across the nail plate to reach andimmobilize fungal spores in the nail plate and nail bed. A particularlypreferred second antifungal nail coat composition for a two-coatcomposition embodiment preferably comprises terbinafine at aconcentration in the range of about 0.1 to not more than about 10 weightpercent, an effective film-forming amount of a hydrophilic film-formingpolymer and a pharmaceutically acceptable, volatile carrier as describedabove as the remainder. The volatile carrier in the first and secondcompositions can be the same or different as desired.

The hydrophilic polymer may be a film-forming polymer comprising avinylpyrrolidone monomer unit, including a homopolymer, (i.e.,polyvinylpyrrolidone), a copolymer and a complex thereof, a gum, aresin, or the like. The term “copolymer” as used herein and in theappended claims means any polymer comprising two or more differentmonomer repeating units and includes polymers commonly referred to as“terpolymers,” “tetrapolymers” and the like.

Exemplary film-forming polymers containing vinylpyrrolidone (VP) monomerunits, are polyvinylpyrrolidone (PVP), sold in a range of viscositygrades, and varying weight average molecular weights in the range ofabout 8,000 to about 3,000,000 Daltons (PVP K homopolymer series). PVPis sold under the trade name KOLLIDON® CL by BASF Corporation. A USPgrade of povidone (PVP) is preferred. Exemplary film-forming copolymersinclude vinylpyrrolidone/vinylaacetate (VA) copolymers available in arange of mole ratios of VP/VA such as the PVP/VA copolymer series soldby ISP, and the like. An exemplary VP complex is povidone-iodine(PVP-I).

The hydrophilic polymer preferably is a polyvinylpyrrolidone having a“K” value of about 30 (i.e., a weight average molecular weight in therange of about 45,000-60,000 Daltons.

Exemplary gums include agar gum, carrageenan gum, ghati gum, kara-yagum, rhamson gum, xanthan gum and the like.

Exemplary resins include carbomer, a polyacrylic acid polymer lightlycross-linked with polyalkenyl polyether. It is commercially availablefrom Noveon Inc. (Cleveland, Ohio) under the designation “CARBOPOL®.” Aparticularly preferred grade of carbomer is that designated as“CARBOPOL® 940.” Other polyacrylic acid polymers suitable for use arethose commercially available under the designation “PEMULEN®” (NoveonInc.) and POLYCARBOPHIL™ (A. H. Robbins Company, Inc., Richmond, Va.),is a polyacrylic acid cross-linked with divinyl glycol. The PEMULEN®polymers are copolymers of C₁₀ to C₃₀ alkyl acrylates and one or moremonomers of acrylic acid, methacrylic acid or one of their simple esterscross-linked with an allyl ether of sucrose or an allyl ether ofpentaerythritol.

There is no limitation on the form (i.e., liquid or powder) ofhydrophilic film-forming polymer used, or the amount used as long as thenail coat composition can be easily applied to the nail and form a filmthereon.

The present dual action antifungal nail coat composition can include oneor more substantially non-volatile penetration enhancers, auxiliaryanti-infectives, such as antibacterial agents, antiseptic agents, andthe like, and mixtures thereof. In two-coat composition embodiments, oneor more substantially non-volatile penetration enhancers can be includedin either the first antifungal nail coat composition or the secondantifungal nail coat composition or in both. The penetration enhancersin the antifungal nail coat compositions of this invention preferablyenhance the penetration of the drug into the nail as well as thesurrounding skin tissue area.

Among preferred skin penetration enhancers are ethanol, propyleneglycol, glycerol, ethyl laurate, isopropyl palmitate, isopropylmyristate, laurocapram (AZONE®), dioxolanes (described in U.S. Pat. No.4,861,764), macrocyclic ketones, 1-decyl-thiolthyl-2-pyrrolidone(HP-101), oxazolidones and biodegradable penetration enhancers(described in U.S. Pat. Nos. 4,980,378 and 5,082,866 to Wong et al. suchas alkyl-2-(N,N-disubstituted amino) alkanoates (e.g.,dodecyl-2-(N,N-dimethylamino) isopropionate (DDAIP)), N,N-disubstitutedamino alkanol alkanoates) and mixtures thereof. Aliphatic and aromaticalcohols are primarily nail penetration enhancers.

The penetration enhancer is present in an amount sufficient to enhancethe penetration of the antifungal agent. The specific amount variesnecessarily according to the desired release rate and the specificantifungal agent used. Generally, the penetration enhancer is present inan amount ranging from about 0.1 weight percent to about 25 weightpercent, based on the total weight of the antifungal nail coatcomposition. Preferably, the penetration enhancer is present in anamount ranging from about 0.1 weight percent to about 10 weight percent,more preferably, in an amount ranging from about 0.5 weight percent toabout 5 weight percent of the antifungal nail coat composition.

In general, suitable penetration enhancers can be chosen from thoselisted above, as well as aliphatic and aromatic alcohols, sulfoxides,fatty acids, fatty acid esters, polyols, amides, surfactants, terpenes,alkanones, organic acids and mixtures thereof. See generally Chattaraj,S.C. and Walker, R. B., Penetration Enhancer Classification, pp.5-20 inMaibach, H. I., and Smith, H. E., (eds.), Percutaneous PenetrationEnhancers, CRC Press, Inc., Boca Raton, Fla. (1995) and Büyüktimkin, N.,et al., Chemical Means of Transdermal Drug Permeation Enhancement, inGhosh, T. K., and Pfister, W. R. (eds.) Transdermal and Topical DrugDelivery Systems, Interpharm Press, Inc., Buffalo Grove, Ill. (1997).

Suitable alcohols include, without limitation, ethanol, propanol,butanol, pentanol, hexanol, octanol, nonanol, decanol, 2-butanol,2-pentanol, benzyl alcohol, phenoxyethanol, caprylic alcohol, decylalcohol, lauryl alcohol, 2-lauryl alcohol, myristyl alcohol, cetylalcohol, stearyl alcohol, oleyl alcohol, linolyl alcohol, linolenylalcohol and mixtures thereof. Volatile aliphatic alcohols having 2 toabout 5 carbon atoms can provide a dual function of serving both asvolatile carrier and penetration enhancer. The aromatic alcohols, suchas benzyl alcohol, phenoxyethanol, and the like can provide a dualfunction of serving both as a substantially non-volatile, permeationenhancer and auxiliary anti-infective. Preferred alcohols are ethanoland benzyl alcohol.

Suitable sulfoxides include dimethylsulfoxide (DMSO),decylmethylsulfoxide, and mixtures thereof.

Suitable fatty acids include valeric, heptanoic, pelargonic, caproic,capric, lauric, myristic, stearic, oleic, linoleic, linolenic, caprylic,isovaleric, neopentanoic, neoheptanoic, neononanoic, trimethyl hexanoic,neodecanoic and isostearic acids, and mixtures thereof.

Suitable fatty acid esters include isopropyl n-butyrate, isopropyln-hexanoate, isopropyl n-decanoate, isopropyl myristate, isopropylpalmitate, octyldodecyl myristate, ethyl acetate, butyl acetate, methylacetate, methylvalerate, methylpropionate, diethyl sebacate, ethyloleate, ethyl laurate and mixtures thereof. Suitable polyols includepropylene glycol, polyethylene glycol, ethylene glycol, diethyleneglycol, triethylene glycol, dipropylene glycol, glycerol, propanediol,sorbitol, dextrans, butanediol, pentanediol, hexanetriol, and mixturesthereof.

Suitable amides include urea, dimethylacetamide, diethyltoluamide,dimethylformamide, dimethyloctamide, dimethyldecamide, pyrrolidonederivatives, 1-alkyl-4-imidazolin-2-one, cyclic amides,hexamethylenelauramide and its derivatives, diethanolamine,triethanolamine and mixtures thereof. Suitable pyrrolidone derivativesinclude 1-methyl-2-pyrrolidone, 2-pyrrolidone, 1-lauryl-2-pyrrolidone,1-lauryl-4-carboxy-2-pyrrolidone, 1-methyl-4-carboxy-2-pyrrolidone,1-hexyl-4-carboxy-2-pyrrolidone, 1-decylthioethyl-2-pyrrolidone(HP-101), N-cyclohexylpyrrolidone,1-methyl-4-methoxycarbonyl-2-pyrrolidone,1-hexyl-4-methoxycarbonyl-2-pyrrolidone,1-lauryl-4-methoxycarbonyl-2-pyrrolidone,N-dimethylaminopropylpyrrolidone, N-cocoylpyrrolidone,N-tallowylpyrrolidone, fatty acid esters ofN-(2-hydroxymethyl)-2-pyrrolidone, and mixtures thereof. Suitable cyclicamides include, 1-dodecylazacycloheptan-2-one (laurocapram, AZONE®),1-geranylazacycloheptan-2-one, 1-farnesylazacycloheptan-2-one,1-geranylgeranylazacycloheptan-2-one,1-(3,7-dimethyloctyl)azacycloheptan-2-one, 1-(3,7,11-trimethyloctyl)azacycloheptan-2-one, 1-geranylazacyclohexan-2-one,1-geranylazacyclopentan-2,5-dione, 1-farnesylazacyclopentan-2-one, andmixtures thereof.

Suitable surfactants include anionic surfactants, cationic surfactants,nonionic surfactants, amphoteric surfactants, bile salts and lecithin.Suitable anionic surfactants include sodium laurate, sodium laurylsulfate, and mixtures thereof. Suitable cationic surfactants includecetyltrimethylammonium bromide, tetradecyltrimethylammonium bromide,benzalkonium chloride, octadecyltrimethylammonium chloride,cetylpyridinium chloride, dodecyltrimethylammonium chloride,hexadecyltrimethylammonium chloride, and mixtures thereof. Suitablenonionic surfactants includeα-hydro-ω-hydroxypoly(oxyethylene)-poly(oxypropyl) poly(oxyethylene)block copolymers, polyoxyethylene ethers, polyoxyethylene sorbitanesters, polyethylene glycol esters of fatty alcohols, and mixturesthereof. Suitable α-hydro-ω-hydroxy-poly(oxyethylene)-poly(oxypropyl)poly(oxyethylene) block copolymers include Poloxamers 182, 184, 231, andmixtures thereof. Suitable polyoxyethylene ethers include PEG-4 laurylether (BRIJ® 30), PEG-2 oleyl ether (BRIJ® 93), PEG-10 oleyl ether(BRIJ® 96), PEG-20 oleyl ether (BRIJ® 99), and mixtures thereof.Suitable polyoxyethylene sorbitan esters include the monolaurate (TWEEN®20) the monopalmitate (TWEEN® 40), the monostearate (TWEEN® 60), themonooleate (TWEEN® 80), and mixtures thereof. Suitable polyethyleneglycol esters of fatty acids include polyoxyethylene (8) monostearate(MYRJ® 45), polyoxyethylene (30) monostearate (MYRJ® 51), thepolyoxyethylene (40) monostearate (MYRJ® 52), and mixtures thereof.

Suitable amphoteric surfactants include, without limitation thereto,lauramidopropyl betaine, cocamidopropyl betaine, lauryl betaine,cocobetaine, cocamidopropylhydroxysultaine, aminopropyl laurylglutamide,sodium cocoamphoacetate, sodium lauroamphoacetate, disodiumlauroamphodiacetate, disodium cocoamphodiacetate, sodiumcocoamphopropionate, disodium lauroamphodipropionate, disodiumcocoamphodipropionate, sodium lauriminodipropionate, disodiumcocoamphocarboxymethylhydroxypropylsulfate, and the like.

Suitable bile salts include sodium cholate, sodium salts of laurocholic,glycolic and desoxycholic acids, and mixtures thereof.

Suitable terpenes include D-limonene, α-pinene, β-enrene, α-terpineol,terpinen-4-ol, carvol, carvone, pulegone, piperitone, menthone, menthol,geraniol, cyclohexene oxide, limonene oxide, α-pinene oxide,cyclopentene oxide, 1,8-cineole, ylang ylang oil, anise oil, chenopodiumoil, eucalyptus oil, and mixtures thereof. Suitable alkanones includeN-heptane, N-octane, N-nonane, N-decane, N-undecane, N-dodecane,N-tridecane, N-tetradecane, N-hexadecane, and mixtures thereof. Suitableorganic acids include citric acid, succinic acid, salicylic acid,salicylates (including the methyl, ethyl and propyl glycol derivatives),tartaric acid, and mixtures thereof.

A preferred, substantially non-volatile, penetration enhancer comprisesan N,N-di(C₁-C₈) alkylamino substituted, (C₄-C₁₈) alkyl (C₂-C₁₈)carboxylic ester or pharmaceutically acceptable acid addition saltthereof. As used herein, the term “(C₄-C₁₈) alkyl (C₂-C₁₈) carboxylicester” means an ester of a (C₄-C₁₈) alcohol and a (C₂-C₁₈) carboxylicacid. The term “N,N-di(C₁-C₈) alkylamino substituted,” in reference to a(C₄-C₁₈) alkyl (C₂-C₁₈) carboxylic ester means that either the alcoholportion or the carboxylic acid portion from which the ester is preparedbears an amino substituent NR_(x)R_(y), wherein R_(x) and R_(y) are eachindependently a (C₁-C₈) alkyl group. Preferably R_(x) and R_(y) are bothmethyl groups.

Preferred are dodecyl-2-(N,N-dimethylamino) propionate (DDAIP);dodecyl-2-(N,N-dimethylamino)-acetate (DDAA);1-(N,N-dimethylamino)-2-propyl dodecanoate (DAIPD);1-(N,N-dimethylamino)-2-propyl myristate (DAIPM);1-(N,N-dimethylamino)-2-propyl oleate (DAIPO); and pharmaceuticallyacceptable acid addition salts thereof.

A particularly preferred skin permeation enhancer is DDAIP, alone or incombination with an auxiliary permeation enhancer. DDAIP.HCl isavailable from Steroids, Ltd. (Chicago, Ill.) and Pisgah Laboratories(Pisgah Forest, N.C.). Particularly preferred is the hydrochloride ofDDAIP (DDAIP.HCl). The preparation of DDAIP and crystalline acidaddition salts thereof is described in U.S. Pat. No. 6,118,020 toBüyüktimkin, et al., which is incorporated herein by reference. Longchain similar amino substituted, alkyl carboxylic esters can besynthesized from readily available compounds as described in U.S. Pat.No. 4,980,378 to Wong, et al., which is incorporated herein by referenceto the extent that it is not inconsistent herewith.

The term “anti-infective agent” as used herein includes a topicalantibacterial, antiseptic, or the like, that can augment the efficacy ofthe dual action antifungal nail coat composition. Suitable antibacterialagents include bacteriostatic preservatives, such as benzyl alcohol,phenoxyethanol, phenethylalcohol, iodopropynl butyl carbamate, paraben,and the like. Benzyl alcohol is particularly preferred, and when presentcan serve a dual purpose as penetration enhancer and anti-infective.

Suitable antiseptic agents include alcohol (i.e., ethanol, isopropanol),halogen containing compounds, (i.e., povidone-I, triclosan, and thelike); quaternary ammonium compounds (i.e., benzethonium chloride,cetylpyridimum chloride, and the like).

Those skilled in the art will recognize that one or more of theforegoing ingredients can serve more than one function.

A preferred dual action, one-coat type antifungal nail coat compositionembodiment comprises:

-   -   an effective fungicidal amount of an antifungal agent;    -   a permeation enhancing amount of a substantially non-volatile,    -   permeation enhancer selected from the group consisting of an        N,N-di(C₁-C₈) alkylamino substituted, (C₄-C₁₈) alkyl (C₂-C₁₈)        carboxylic ester or pharmaceutically acceptable acid addition        salt thereof, a pharmaceutically acceptable alcohol, and        mixtures thereof;    -   a film-forming amount of a hydrophilic polymer; and    -   a pharmaceutically acceptable, volatile organic carrier.

Preferably, the one-coat antifungal nail coat composition is asubstantially clear formulation.

A preferred dual action, one-coat type embodiment of antifungal nailcoat composition comprises on a total composition weight basis:

-   -   antifungal agent in an amount in the range of about 0.1 to about        20 weight percent, more preferably in the range of about 0.5 to        about 15 weight percent; most preferably in the range of about 1        to about 5 weight percent;    -   a substantially non-volatile permeation enhancer in a total        amount in the range of about 0.1 to about 25 weight percent,        more preferably in the range of about 1 to about 10 weight        percent;    -   a hydrophilic film-forming polymer in an amount in the range of        about 0.1 to about 5 weight percent, more preferably in the        range of about 0.25 to about 1 weight percent; and    -   the remainder comprising a pharmaceutically acceptable volatile        organic carrier. A preferred volatile organic carrier is an        aliphatic alcohol preferably present in an amount in the range        of about 50 to about 99.5 weight percent, more preferably in the        range of about 85 to about 99, based on a total composition        weight basis.

A particularly preferred substantially clear, dual-action, one-coat typeantifungal nail coat composition comprises on a total composition weightbasis: terbinafine hydrochloride present in an amount in the range ofabout 0.5 to about 10 weight percent, more preferably in the range ofabout 1 to about 5 weight percent;

DDAIP.HCl present in an amount in the range of about 0.1 to about 25weight percent, more preferably in the range of about 0.1 to about 10weight percent;

-   -   benzyl alcohol present in an amount in the range of about 0.1 to        about 10 weight percent, more preferably in the range of about        0.5 to about 1.5 weight percent;    -   polyvinylpyrrolidone present in an amount in the range of about        0.1 to about 5 weight percent, more preferably in the range of        about 0.25 to about 1 weight percent; and    -   the remainder being ethanol.

In a two-coat type embodiment utilizing first and second antifungal nailcoat compositions, the second antifungal nail coat compositionpreferably is formulated so that the film coat deposited on fingernailsis substantially more resistant to ready removal with water than theprimer film coat deposited on toenails.

A particularly preferred, two-coat type dual action antifungal nail coatcomposition comprises, in the first or primer antifungal nail coatcomposition, on a total composition weight basis, about 10 weightpercent terbinafine in ethanol, and in the second antifungal nail coatcomposition preferably not more than about 5 weight percent terbinafine.A presently preferred second or depot antifungal nail coat compositioncomprises about 20 parts by weight polyvinylpyrrolidone, about 3 partsby weight terbinafine, and about 47 parts by weight ethanol.

Based on in vitro test studies using human nail clippings, it was foundthat terbinafine applied as a 10% solution in ethanol can diffuse acrossa nail membrane and, in a period of about one hour, can reach aconcentration above the minimum inhibition concentration (MIC) forfungi.

Fungal infection of a toenail or fingernail may be ameliorated orprevented by a one-coat method, or a two-coat method as described below.

A one-coat type dual action antifungal nail coat composition can beapplied to provide a substantially uniform fungicidal coating on afungally susceptible or infected nail and adjacent skin tissue andmaintained in contact therewith for a period of at least about 0.5 hour.In a one-coat method, the nail coat composition can be removedsubsequently by rinsing with water. In a multiple-coat method, thecomposition can be re-applied at least twice with or without anintervening water rinse. The nail coat composition is preferably appliedin a daily regimen for a period sufficient to achieve fungicidalefficacy.

A two-coat type dual action antifungal nail coat composition of thisinvention can be applied by the following multiple-coat method.

(1) A first antifungal nail coat composition containing an effectivefungicidal amount of antifungal agent is applied at least once to aninfected fingernail or toenail, and surrounding skin area, to provide anactive fungicidal primer coat;

(2) The active fungicidal primer coat is allowed to substantially dryfor about 10 minutes or until the fungicidal primer-coated nail issubstantially dry to the touch; and then

(3) The substantially dry fungicidal primer-coated nail is coated with asufficient fungicidal amount of a second antifungal nail coatcomposition to provide a fungicidal film coat thereon for furtherrelease of antifungal agent to the nail.

In the initial period of a fungicidal regimen with a two-coat type dualaction antifungal nail coat composition, multiple applications of thefirst antifungal nail coat composition can be applied, by performingsequential steps (1) and (2) at least twice before performing step (3)to further optimize the bioavailability of antifungal agent.

The methods of this invention are preferably practiced daily until newnail growth is visibly free of fungal infection.

It was found that the practice of a two-coat method of this inventionwith terbinafine extended the residence time of the terbinafine appliedfrom the first antifungal nail coat composition, that the hydrophilicpolymer film coat of the second antifungal nail coat compositionpromoted the formation of an internal and external barrier membrane, andthat a high efficacy in ameliorating or preventing onychomycosis withina relatively short period of about four weeks was achieved.

The nail coat compositions of the present invention can be applied tothe nail by any convenient method, such as by brushing or spraying.Preferably the applied composition is substantially dry to the touchwithin a period in the range of about 0.5 to about 10 minutes, morepreferably within a period in the range of about one to about fiveminutes, depending upon the amount of volatile organic carrier present.

The fungicidal nail coat compositions may be provided in kit form withinstructional indicia included therein for use. The first and secondantifungal coat compositions of a two-coat dual action, antifungal nailcoat composition may be individually packaged in similar or dissimilarshaped packages or are color coded to visibly distinguish the first andsecond compositions from one another to aid the user in following thetherapeutical order of application.

Instructional indicia includes, without limitation, printed media, auralmedia, visual aids, electronic media or a combination thereof whichinform and instruct the user. Printed media includes, but is not limitedto, labels, pamphlets, books, flyers and the like. Aural media includes,but is not limited to, tape recordings, audio compact disks, records,and the like. Visual aids include, but are not limited, to photographs,slides, movies, videos, DVDs, and the like. Electronic media includesall forms of electronic data storage media, such as, but not limited to,diskettes, interactive CD-ROMs, interactive DVDs, and the like.

The following examples are intended to illustrate, but not limit, thepresent invention.

EXAMPLE 1

The preliminary efficacy and safety of terbinafine hydrochloride in atwo-coat type dual action, antifungal nail coat composition and methodof this invention was studied with patients having toenail and/orfingernail fungal infection. The patients participated in an open label,single hospital pilot clinical study over a period of three months.

Up to 20 patients were selected assessed as having mild to severeonychomycosis, as measured by using a scale of infection, based on nailplate separation from the nail bed, hyperkeratosis, and discoloration.The extent of onychomycosis, hyperkeratosis, and discoloration wereassessed using the following scale ratings:

-   -   Onychomycosis    -   0=absence of separation of nail plate from nail bed.    -   1=≦50% separation of nail plate.    -   2=>50% but s 75% separation of nail plate.    -   3=>75% separation of nail plate.    -   Hyperkeratosis    -   0=absence of subungual debris.    -   2=thickening of ≦50% of the subungual region.    -   2=>505 but ≦75% thickening of the subungual region.    -   3=>75% thickening of the subungual region.    -   Discoloration    -   0=absence of any unusual coloration (white, yellow, etc.) of the        nail plate.    -   1=discoloration extending to ≦50% of the nail plate.    -   2=discoloration extending to >50% but 5.75% of the nail plate.    -   3=discoloration extending to >75% of the nail plate.

For inclusion in the study, the criteria were: onychomycosis patientsbetween the ages of 18-70 years, having a nail involvement of at least25% of the whole nail surface that included any destroyed or missingpart of the nail plate. Onychomycosis of the finger nail or toenail wasconfirmed as follows by KOH staining microscopic examination and fungalculture.

The nail plate and hard debris were softened by leaving the fragments,along with several drops of potassium hydroxide (25% KOH with 5%glycerine), in a watch glass covered with a petri dish for 24 hours.Light microscope was used for the fungal examination. The smallfragments of scale were placed on a microscope slide and a coverslip wasapplied. The preparation was studied carefully at low power.Dermatophytes appear as translucent branching, rod-shaped filaments ofuniform width. If the presence of hyphae is confirmed by examinationwith the 40× objective, the test result is judged as positive.

Fungal culture was carried out using the standard culture medium,Sabouraud's agar, (agar 18 g, peptone 10 g, glucose 40 g, distilledwater 1000 ml). Most medically important fungi are grown aerobically onthis culture medium over an incubation period of about 24 hours to about48 hours at a temperature of about 28° C.

The criteria for exclusion from the study were: onychomycosis caused bymolds (Candida sp.); hypersensitivity to terbinafine; abnormal liverfunction (twice the upper limit value); receipt of topical treatmentwithin 2 weeks or oral treatment within two months; concurrent treatmentwith H-blockers, antacid, rifampin, phenobarbital, phenytoin,carbamazepine, terfenadine (e.g. SELDANE™) or digoxin; use of anyinvestigational drugs with one month; psoriasis or history of psoriasis;serious concurrent disease that might influence the trial; and pregnantwomen or nursing mothers.

Twenty patients (six females, 14 males) between the ages of 35-59 years,with an average age of 46 years, met the inclusion criteria. Of these 20subjects, 17 completed 12 weeks of treatment. At the start of the study,the extent of onychomycosis was assessed as mild (i.e., ≦40% infectednail) for 15%, and as severe (i.e., >40% infected nail) for theremaining 85% of the 20 patients. Of the 20 patients, 45% of thepatients had separation of nail plate; 45% had hyperkeratosis; and 10%had discoloration.

The primary efficacy criteria were mycological cure based on achieving anegative KOH staining microscopic examination and a negative fungalculture.

The secondary efficacy criteria were the physicians's assessment of themycological cure and clinical efficacy. Clinical efficacy evaluation wasassessed as follows: “Cleared” (i.e., no signs of mycosis, withoutresidual nail deformity, no requirement for further therapy); “MarkedlyImproved” (i.e., minimal nail involvement with significantly decreasedsigns of mycosis; and “Slightly to Moderately Improved” (i.e., slight tomoderate reduction in extent of nail involvement and signs of mycosis).

After the completion of the study, the clinical safety and efficacy ofadministration were analyzed by investigators based on adverse events,KOH staining microscopic examination, fungal culture, clinical efficacyassessment (i.e., planimetric measurement of the involved area,photographic comparison of new nail growth, and reduction in extent ofnail involvement) and the physician's global evaluation.

The primary safety parameters included adverse events, vital signs,clinical laboratory tests, physical examinations, and electrocardiograms(ECG).

The patients assigned to the study were each provided with two bottleshaving brush applicators, each bottle containing nail coat composition(about 20 grams in each bottle), and identified as “A” and “B”. Bottle“A” contained terbinafine hydrochloride 10% (weight/weight) in ethanol.Bottle “B” contained 20 parts by weight polyvinylpyrrolidone (PVP,KOLLIDON® 30, weight average molecular weight in the range of about45,000-60,000 Daltons), 3 parts by weight terbinafine hydrochloride, and47 parts by weight ethanol.

The patients were instructed to cleanse their feet or hands by usingwarm water, and cut or clean infected nails as much as possible, but notto file the nails. The patients were also instructed to apply theantifungal nail coat composition on the infected nail directly once eachnight substantially immediately after washing their feet.

The patients were instructed to first apply Solution A with the brush,let Solution A dry, and then apply Solution B with the brush and letSolution B dry. There were no limitations to avoid wetting or washingtheir feet. The coating was easy to wash off before re-applying the dualaction antifungal nail coat composition. The patients were instructedthat, after washing off the coating, the patient re-apply the antifungalnail coat composition right away. The doctors encouraged the patients touse the antifungal nail coat composition on a daily basis, especiallyfor the first month.

The efficacy, based on primary efficacy (mycological cure), clinicalefficacy (appearance of the new nail, disappearance of signs andsymptoms), and total efficacy (i.e., both mycological evaluation andclinical evaluation assessments) at the end of the first, second andthird month of the study period is summarized in Table 1.

TABLE 1 Month 1 Month 2 Month 3 Patients % Patients % Patients %Evaluated 18 100 17 100 17 100 Primary Efficacy 7 38.9 8 47.1 9 52.9Clinical Efficacy 6 33.3 10 58.8 16 94.1 Total Efficacy 7 38.9 8 47.1 952.9

As shown in Table 1, based on the assessed change in nail involvement,change in signs of fungal infection, and new nail growth, the clinicalefficacy (including patients rated as “slightly to moderately improved,”“markedly improved,” and “cleared”) at the end of the first, second, andthird month of treatment, was 33.3%, 58.8% and 94.1%, respectively.

As shown in Table 2, the number of patients initially assessed as havingsevere onychomycosis decreased at the end of the first, second, andthird month of the study period, and concurrently, the number ofpatients assessed as having mild onychomycosis increased.

TABLE 2 Month 0 Month 1 Month 2 Month 3 Onychomycosis Patients %Patients % Patients % Patients % Evaluated 20 100 18 100 17 100 17 100Mild (≦40%) 3 15 4 22.2 4 23.5 6 35.3 Severe (≧40%) 17 85 14 77.8 1376.5 11 64.7

One patient having “mild” onychomycosis and one patient having “severe”onychomycosis were judged as showing significant improvement at the endof the third month.

During the study period, the patients also maintained a diary from whichthe patient's experiences of any adverse events were recorded. Noadverse events were reported by any of the patients during the studyperiod.

It is recognized that new nail growth takes time. The nail reportedlygrows continuously at the rate of 3-4 millimeters (mm) a month (0.112 to0.132 mm a day), so some 4.5-5 months are required for a completerenewal of the nail. It is also recognized that the speed of nail growthdiffers between individuals as well as age groups (nail growth beingmore rapid in the young), and that certain health disorders andmedications can upset the rate of growth. Thus, mycological evaluationwas judged as the most proper objective primary efficacy criteria tobest predict full future clinical efficacy. The efficacy of the two-coattype dual action antifungal nail composition within the short-term studyperiod as judged safe and effective for ameliorating onychomycosis ofvarying intensity.

EXAMPLE 2

The uptake of antifungal agent by a nail substrate was evaluated invitro using human nail clippings collected from one individual. The nailclippings were cleaned and extracted with anhydrous ethyl alcohol forseveral days before applying the antifungal agent, terbinafinehydrochloride.

About 15 mL of four antifungal containing solutions each were preparedcomprising the following indicated amount, on a total composition volumebasis, terbinafine hydrochloride, volatile organic carrier (ethanol),film-forming hydrophilic polymer (polyvinylpyrrolidone (PVP)), orpenetration enhancer dodecyl-2-(N,N-dimethylamino) isopropionatehydrochloride (DDAIP.HCl)).

Solution A. 10 weight percent terbinafine hydrochloride in anhydrousethyl alcohol.

Solution B. 10 weight percent terbinafine hydrochloride and 10 weightpercent PVP (KOLLIDON® 30, BASF) in anhydrous ethyl alcohol.

Solution C. 10 weight percent terbinafine hydrochloride and 0.5 weightpercent DDAIP.HCl in anhydrous ethyl alcohol.

Solution D. 10 weight percent terbinafine hydrochloride and 1 weightpercent DDAIP.HCl in anhydrous ethyl alcohol.

The nail clippings were separately immersed in about 5 mL of each ofsolution A, B, C, and D (solid:liquid ratio of about 1:10), and theuptake of terbinafine was determined by measuring the concentration ofterbinafine in the solution as a function of time over a period startingfrom immersion to about 24 hours. Measurement was made using HighPerformance Liquid Chromatography (HPLC) technique using a WatersAlliance HPLC. (Waters Symmetry C18, 3.5 nm 4.2×75 mm column wasequipped for the separations, UV 224 nm for detection, flow rate 1.5mL/min., injection 20 μL). The buffer was composed of two partstriethylamine and 1000 parts of deionized water and the pH was adjustedto pH 7 with phosphoric acid. The mobile phase composition was 25 partsof buffer and 75 parts acetonitrile.

As shown graphically in FIG. 1, an initially fast decrease in thesolution concentration of terbinafine was observed in all cases, whichgradually approached equilibrium after about five hours, remainingsubstantially unchanged up to 24 hours, indicating that saturation hadbeen reached. Uptake from Solution A reached equilibrium in less thanabout one hour, somewhat sooner than from Solutions B, C or D. In allcases, the average amount of terbinafine uptake was judged to be about5.2 mg/100 mg nail or about 5.2% on a nail weight basis.

The terbinafine-treated nail clippings were then separately recoveredfrom each test solution and rinsed with 10 mL of ethyl alcohol to removeantifungal liquid from the surface cavity. The rinsed nail clippingsfrom each test were then separately immersed in another 5 mL portion ofanhydrous ethyl alcohol to assess the rate of terbinafine release fromthe nail structure, by determining the concentration of terbinafinehydrochloride released as a function of time using the HPLC techniquedescribed above. The amount of terbinafine hydrochloride initiallyreleased from the nail, based on release measurements over a period ofabout 48 hours, was greater from nail treated with Solution A, than fromnail treated with Solution B, C, or D. As shown graphically in FIG. 2,the amount of terbinafine hydrochloride retained in the nail reachedequilibrium in a period of about 10 hours. The order of efficacy oftreatment was Solution D>Solution C>Solution B>Solution A.

FIG. 3 graphically shows the retention of terbinafine hydrochlorideupdate in the nails treated with Solutions C and D. The data indicatedthat the film-forming polymer in Solution B, and the penetrationenhancer in Solutions C and D, contributed beneficially to increasingthe residence time of terbinafine in the nail.

EXAMPLE 3

The permeation of terbinafine hydrochloride by human nail clippings as afunction of time was compared using Solution A and C, prepared as inExample 2. Nail clippings having a substantially similar dry thickness(+/−5%) were selected. A selected nail clipping was anchored by beingplaced between two open metal frames, a sealant material was placedbetween the rim of the frame and the edge of the nail, and the edges ofthe nail were then compressed to stabilize the nail and provide a nailholder. The nail holder thus had an opening for permeation and wassealed against leakage when the anchored nail was placed in a horizontalFranz diffusion cell as a permeable membrane. The volume capacity ofeach of the donor cell and receiving cell was 3 mL, and the permeationarea of about 78.5 square mm. The donor solution was the antifungalsolution (Solution A or Solution C) and the receiver solution wasanhydrous ethyl alcohol. The receiver solution was sampled periodicallyover a period of up to about 100 hours, and analyzed by HPLC, as inExample 2.

The cumulative permeation of terbinafine hydrochloride in the receiveris graphically shown in FIG. 4, and indicates an enhanced permeation ofterbinafine hydrochloride through the nail from Solution C containing10% terbinafine hydrochloride and 0.5% DDAIP.HCl over that of Solution Acontaining 10% terbinafine hydrochloride in anhydrous ethyl alcohol.

EXAMPLE 4

This example illustrates formulations for one-coat type dual action,antifungal nail coat compositions, (A), (B), (C), (D) and (E).

TABLE 3 WEIGHT PERCENT INGREDIENT (A) (B) (C) (D) (E) Terbinafine•HCl 15 10 1 1 DDAIP•HCl 0.5 0.5 0.5 2.5 5 PVP, USP 0.5 0.5 0.5 0.5 0.5 Benzylalcohol 0.75 0.75 0.75 0.75 0.75 Ethanol to 100% q.s. q.s. q.s. q.s.q.s. q.s. = quantity sufficient

EXAMPLE 5

This example illustrates, in a recognized guinea pig model ofdermatophytosis caused by Trichophyton mentagrophytes (T.mentagrophytes) (ATCC 24953), the in vivo clinical and fungicidalefficacy of one-coat type dual action, antifungal nail coat compositionscontaining varying amounts of terbinafine hydrochloride and ofpenetration enhancer, DDAIP.HCl. Ten compositions were prepared havingthe amounts indicated in Table 4.

TABLE 4 Weight Percent Ingredient Terbinafine PVP, Benzyl EthanolExample HCl DDAIP•HCl USP Alcohol to 100% 5(A) None None 0.5 0.75 q.s.(control) 5(B) None 0.5 0.5 0.75 q.s. 5(C) 1 None 0.5 0.75 q.s. 5(D) 5None 0.5 0.75 q.s. 5(E) 10 None 0.5 0.75 q.s. 5(F) 1 0.5 0.5 0.75 q.s.5(G) 1 2.5 0.5 0.75 q.s. 5(H) 1 5   0.5 0.75 q.s. 5(I) 5 0.5 0.5 0.75q.s. 5(J) 10 0.5 0.5 0.75 q.s.

The procedures of the in vivo evaluation protocol used were incompliance with the Animal Welfare Act, the Guide for the Care and Useof Laboratory Animals, and the Office of Laboratory Animal Welfare. Theprotocol also was approved by the Institutional Animal Care and UseCommittee (IACUC), and the IACUC Guidelines were followed. Theevaluation was carried out at the Center for Medical Mycology andMycology Reference Laboratory of Case Western Reserve University,Cleveland, Ohio.

Male albino Guinea-Pigs Harlan-Sprague-Dawley (San Diego, Calif.) havinga body weight of about 400 to about 450 grams were acclimated for aminimum of five days prior to use. The environmental controls for theanimal room were set to maintain a temperature in the range of about 16to about 22° C., a relative humidity in the range of about 30 to about70%, and a 12 hour light/12 hour dark cycle. Guinea pigs are naturallysusceptible to dermatophyte infection and need no special manipulation,such as immunosuppression.

Each test guinea pig was anesthetized with an intramuscular (IM)injection of 0.1 ml of an anesthetic cocktail of xylazine, ketamine andacepromazine (3:3:1 by volume). Using an electric shaver, hair wasclipped on the left side of the guinea pig's back. A closer shave wasgiven with a safety razor. Using a stencil, a shaved skin area of about2.5×2.5 cm² square was marked in quadrants, and the marked skin area wasabraded with sterile fine grit sandpaper. The guinea pig was theninfected topically by thoroughly rubbing onto the abraded skin a cellsuspension of T. mentagrophytes, (ATCC 24953).

The T. mentagrophytes suspension was prepared by sub-culturing T.mentagrophytes (from frozen stock) on Potato Dextrose Agar (PDA) (DifcoLaboratories) plates and incubating the plates at a temperature of about30° C. for a period of about five to about seven days. The colonies werescraped from the plate using sterile saline solution (NaCl 0.85%). Afterwashing three times with sterile saline solution, the conidia werere-suspended in sterile saline solution. A ten-fold dilution of conidiasuspension was prepared and counted using a hemacytometer. A workingsuspension of conidia was prepared at a final concentration of 1×10⁷Colony Forming Units (CFU) per 100 microliters normal saline solution.The inoculum counts of the ten-fold dilution of T. mentagrophytesworking conidial suspension was checked by plating the suspension ontoSabouraud Dextrose Agar (Difco Laboratories) media, incubating the plateat a temperature of about 30° C. for a period of about three to aboutfour days, and then determining the colony counts.

Three days after the inoculation and infection with the dermatophyte,the guinea pigs were each treated, once daily for a period of sevendays, with 0.1 mL/application of one of the selected nail coatcompositions, 5(A-J), listed in Table 4. Three days after completion ofthe seven-day test period, mycological and clinical efficacy wasexamined.

Mycological efficacy was examined by removing hair samples with asterile forceps from four quadrants, (10 representative hairs perquadrant). The hair samples were planted in a corresponding quadrant ona Potato Dextrose Agar plate and incubated at a temperature of about 30°C. for about two days. Following the two-day incubation period, thefungal growth at the hair root was examined under a stereo-microscope.The effectiveness of a test composition in reducing the number ofmycologically positive hair samples per treated animal group wasexpressed as percentage efficacy relative to the untreated control groupof animals using the following formula: % efficacy=100−(T×100/K), whereT=positive hair in the test group and K=positive hair in the untreatedcontrol group.

Four guinea pigs were tested with the composition of Ex. 5(A) as aplacebo (vehicle control) group (Group 1), five guinea pigs were testedwith each one of the example formulations (Exs. 5(B-J) shown in Table 4,(identified as Groups 2-10 respectively), and one group of four guineapigs was maintained as an infected control group (Group 11).

The hairs from the infected, control guinea pigs (Group 11) showedgrowth of fungal filaments indicating invasion of the hair roots.Substantially similar invasion of the hair roots was noted in theinfected guinea pigs treated with placebo (Group 1) and with thedrug-free composition of Ex. 5(B) (Group 2). All of the compositionscontaining terbinafine HCl, Exs. 5(C-J), had mycological efficacy asdemonstrated by the absence of fungal elements in the hair.

Clinical efficacy was assessed by examining local changes in theappearance of the skin and regrowth of hair at the test sites, using thefollowing numerical score criteria: 0=no lesions; 1=few slightlyerythematous places on the skin; 2=well defined redness, swelling withbristling hairs; 3=large areas of marked redness incrustation, scaling,bald patches, ulcerated in places; 4=partial damage to the integumentand loss of hair; and 5=extensive damage to the integument and completeloss of hair at the site of infection. The assessment of clinicalevaluation in the change of scores per treated animal group wasexpressed as a percentage relative to the untreated control group ofanimals using the following formula: % efficacy=100−(T×100/K), whereT=scores in the test group and K=scores in the untreated control group.

The infected control guinea pigs (Group 11) showed patches of hair lossand readily visible ulcerated or scaly skin. Substantially similarlesions were noted in the Group 1 guinea pigs treated with the placebo,Ex. 5(A), and the Group 2 guinea pigs treated with the drug-freecomposition, Ex. 5(B). All of the terbinafine-containing compositions,Exs. 5(C-J) had clinical efficacy, based on an improved appearance ofthe skin as demonstrated by healthier skin and regrowth of hair in theGroups 3-10 guinea pigs compared to that of guinea pigs treated with theplacebo (vehicle) control and drug-free composition, Exs. 5(A-B).Clinical efficacy was judged optimized at a drug concentration of about1 weight % (Ex. 5(C)) and at a DDAIP penetration enhancer concentrationof about 0.5 weight % (Ex. 5(F)), because increasing the drug content orincreasing the penetration enhancer content did not provide a furtherbeneficial increase in clinical efficacy.

At the end of the study, all surviving animals were sacrificed by anintravenous injection of a euthanasia solution and disposed to theAnimal Resource Center for incineration.

EXAMPLE 6

This example illustrates in vitro the permeability of a one-coat typedual action, antifungal nail coat composition containing terbinafinehydrochloride through hard keratin, using an animal hoof keratin model(horse hoof) and an agar plate diffusion assay.

Three discs, (I, II, and III) were cut from horse hoof keratin to athickness in the range of about 0.5 to about 1 millimeter (mm) (Disc I);a thickness in the range of about 1.1 to about 1.5 mm (Disc II); andthickness in the range of about 1.6 to about 2 millimeter (mm) (DiscIII). The side edges and one face of each disc was coated with Vaselineto prevent seepage of the antifungal drug during agar diffusionevaluation leaving the opposing face exposed.

In one diffusion assay evaluation, three separate antifungal coatsolutions, 6(A), 6(B), 6(C), were prepared, respectively containing 25mg/ml, 0.5 mg/ml, and 1 mg/ml amounts of terbinafine hydrochloride indimethylsulfoxide (DMSO). Each antifungal coat solution was applied tothe exposed face of each selected hoof disc (I, II, and III). Theantifungally-coated face of the hoof disc was then placed in contactwith an agar plate seeded with a lawn of conidial suspension of T.mentagrophytes (ATCC 24953) at a concentration of 5×10⁵, and incubatedfor a period of about eight hours. The zone of inhibition (diameter ofarea remaining clear, i.e., lacking growth) was then measured inmillimeters (mm).

The results showed that, at all concentrations of terbinafinehydrochloride, diffusion took place through the hoof and that thepermeate retained bioactivity. The measured zones of inhibition weregenerally inversely proportional in diameter to the thickness of thehoof disc. Hoof disc II having a thickness in the range of about 1.1 toabout 1.5 mm is judged similar to the thickness of human nails.

EXAMPLE 7

This example simulates the clinical use of a one-coat type dual action,antifungal nail coat composition on human nails using the horse hoofmodel described in Example 6.

The general procedure for simulating clinical use is as follows: Thehorse hoof is cleaned and washed three times with buffer. Sections ofhorse hoof having a thickness of about 100 micrometers are cut using anArbor blade and are sterilized by autoclaving. Individual hoof sectionsare then coated with a selected nail coat composition containing theamount of terbinafine hydrochloride and penetration enhancer shown inCompositions 7(A-H) of Table 5, and left in contact with the nail coatcomposition. For comparison, sections of horse hoof are similarlycontacted with a commercial topical nail lacquer, PENLAC™ containing thesynthetic antifungal, ciclopirox, (Ex. 7(I)). The treated hoof sectionsare then each placed on an agar plate seeded with a lawn of conidialsuspension of T. mentagrophytes (ATCC 24953) at a concentration of5×10⁵, and incubated for a period of about four days at a temperature ofabout 35° C. The zone of inhibition was then measured.

TABLE 5 Weight Percent Ingredient Terbinafine PVP, Benzyl EthanolExample HCl DDAIP•HCl USP Alcohol to 100% 7(A) 1 None 0.5 0.75 q.s. 7(B)5 None 0.5 0.75 q.s. 7(C) 10 None 0.5 0.75 q.s. 7(D) 1 0.5 0.5 0.75 q.s.7(E) 1 2.5 0.5 0.75 q.s. 7(F) 1 5   0.5 0.75 q.s. 7(G) 5 0.5 0.5 0.75q.s. 7(H) 10 0.5 0.5 0.75 q.s. 7(I) Comparative PENLAC ™ Nail LacquerSolution Topical Solution 8% Note: Ex. 7(I) contains 80 mg ciclopirox ina solution base consisting of ethyl acetate, NF; and butyl monoester ofpoly[methylvinylether/maleic acid] in isopropyl alcohol (DermikLaboratories, Inc.).

EXAMPLE 8

This example illustrates the fungicidal activity of one-coat type dualaction, antifungal nail coat compositions containing terbinafinehydrochloride and, as a penetration enhancer, DDAIP.HCl, against threestrains of the dermatophyte Trichopyton rubrum (T. rubrum), nine strainsof the dermatophyte Trichophyton mentagrophytes (T. mentagrophytes), andten strains of the yeast Candida albicans (C. albicans).

Nail coat compositions containing terbinafine hydrochloride, Exs. 8(A),8(B), and drug free control, Ex. 8(C) were prepared having the amountsshown in Table 6 and fungicidal efficacy compared against that of acommercial composition, Ex. 8(D): PENLAC™ Nail Lacquer Solution TopicalSolution 8% (Containing ciclopirox).

TABLE 6 Weight Percent Ingredient Terbinafine PVP, Benzyl EthanolExample HCl DDAIP•HCl USP Alcohol to 100% 8(A) 1 None 0.5 0.75 q.s. 8(B)1 0.5 0.5 0.75 q.s. 8(C) None 0.5 0.5 0.75 q.s. 8(D) ComparativePENLAC ™ Nail Lacquer Solution Topical Solution 8% Note: Ex. 8(D)contains 80 mg ciclopirox in a solution base consisting of ethylacetate, NF; and butyl monoester of poly[methylvinylether/maleic acid]in isopropyl alcohol (Dermik Laboratories, Inc.).

Fungicidal efficacy, based on minimum inhibitory concentration (MIC) andminimum fungicidal concentration (MFC) of the drug, was evaluated usinga broth microdilution assay, as well as an agar diffusion plate assay,measuring the zones of inhibition.

The broth microdilution method was a modification of a NCCLS M38-Astandard method for the susceptibility testing of conidium-formingfilamentous fungi of the National Committee for Clinical LaboratoryStandards (NCCLS). The modified method was developed at the Center forMedical Mycology, University Hospitals of Cleveland, Cleveland, Ohio,based on the method described in Jessup, et al., “AntifungalSusceptibility Testing of Dermatophytes: Establishing a Medium forInducing Conidial Growth and Evaluation of Susceptibility of ClinicalIsolates,”Journal of Clinical Microbiology, 38, 341-344, published bythe American Society for Microbiology (2000), the disclosures of whichare incorporated herein by reference. Based on a multicenter study ofthe reproducibility of the modified method for testing dermatophytes,adoption of the modified method as an amendment to the NCCLS M38-Astandard has been proposed. The modified method is described below.

Dermatophyte isolates are subcultured onto Potato Dextrose Agar (PDA)and incubated at a temperature of about 30° C. for a period of about 4to about 5 days or until good conidiation is produced. T. rubrumisolates are subcultured onto cereal (oatmeal) agar instead of PDA inorder to induce conidia production. A suspension of conidia in sterilesaline is made by gently swabbing the colony surface with a sterileswab. The suspension is allowed to settle for about 5 to about 10minutes and the conidia is counted using a hemocytometer. Workingsuspensions of conidia are prepared in 10 ml RPMI 1604 (DifcoLaboratories) medium to a final concentration of 1 to 3×10³ CFU/ml.Yeast controls are subcultured onto PDA and incubated at a temperatureof about 35° C. for about 48 hours. Yeast inocula are prepared to afinal concentration of 0.5 to 2.5×10³ CFU/ml. For MIC assay, each drugconcentration well and growth control well is inoculated with 100microliters of cell suspension, and the final volume in each microtiterwell is 200 microliters. The dermatophyte plates are incubated at atemperature of about 35° C. for 4 days (yeast controls for 48 hours).Plates are examined visually for 50% and 80% growth inhibition ascompared to the growth control, and MIC results are recorded inmicrograms (μg)/ml. The MIC endpoint is generally defined as the lowestconcentration that inhibited 80% of fungal growth as compared to thegrowth control. To perform the MFC assay, 100 μl is removed from eachmicrotiter well without visible growth and subcultured onto PotatoDextrose Agar plates. The lowest concentration to produce <1-2 coloniesis considered the MFC. (Inoculum removed from the microtiter wells isstreaked for isolation—there are no zones of inhibition).

For the MIC assay, a broth dilution is performed in microtiter wellswith RPMI 1064 as the diluent. The MFC assay is performed bysubculturing the microtiter wells from the MIC test.

For the agar diffusion assay, the standardized inoculum of conidia isapplied to the surface of a Potato Dextrose Agar plate and allowed todry. Wells are then cut into the agar and the test composition is putinto the wells and allowed to diffuse and antifungal activity isevidenced by zones of growth inhibition (i.e., area remaining clear,lacking growth) on the surface of the plates measured in millimeters(mm) diameter.

An agar diffusion assay was performed using Potato Dextrose Agar platesseeded with a lawn of conidial suspension at a concentration of 5×10⁵CFU/ml. The plates were inoculated separately with undiluted testcompositions of Exs. 8(A-D) by adding 200 μl of undiluted testcompositions to wells cut into the agar and allowed to diffuse. Theinoculated plates were then incubated at about 35° C. for 4 days fordermatophytes and 48 hours for yeast. The range and mean diameter inmillimeters (mm) measurement of the Zone of Inhibition (Zone) assays ofthe nail compositions in Table 6 are summarized in Table 6-A below.

TABLE 6-A Ex. 8(A) Ex. 8(B) Ex. 8(C) Ex. 8(D) Zone (mm) Zone (mm) Zone(mm) Zone (mm) Organism Range Mean Range Mean Range Mean Range Mean T.mentagrophytes, n = 9 95-100 97.9  95-100 97.4 13-18 16 30-36 32.2 T.rubrum, n = 3 55-100 84.3 50-98 81 16-18 17.3 30-34 32 C. albicans, n =10 19-30  23.7 18-30 23.8  0-10 8.5 18-30 25.1

The data in Table 6-A show that terbinafine-containing nail coatcompositions, Exs. 8(A) and 8(B) were fungicidally active against allthree organisms and substantially equivalent in activity to one another.The drug-free composition, Ex. 8(C) was judged substantially ineffectiveagainst the yeast, and weakly effective against the two dermatophyticfungi, indicating that such activity was likely attributable toantimicrobial effects contributed by benzyl alcohol and ethanol. Theterbinafine-containing nail coat compositions were judged about threetimes more effective against the dermatophytic fungi, T. mentagrophytes,and T. rubrum, than the commercial ciclopirox-containing nail lacquer,and were substantially equivalent to the commercial nail lacquer againstthe yeast, C. albicans.

EXAMPLE 9

The fungicidal activity of terbinafine hydrochloride against thedermatophytic fungi, T. mentagrophytes, (ATCC 24953), is illustrated inthe modified NCCLS broth dilution assay described in Example 8, based onminimum inhibitory concentration (MIC) and minimum fungicidalconcentration (MFC) as well as an agar diffusion plate assay measuringthe zones of inhibition.

A placebo composition, Ex. 9(A), two nail coat compositions containingterbinafine hydrochloride, Exs. 9(B) and 9(C), and a drug-freecomparative composition, Ex. 9(D) were prepared having the amounts shownin Table 7. Also prepared were dimethylsulfoxide (DMSO) solventsolutions of terbinafine hydrochloride, of the penetration enhancer,DDAIP.HCl, and combinations thereof (Exs. 9(E-H) in the amounts alsoshown in Table 7. Included for comparison, was the commercial PENLAC™Nail Lacquer solution.

TABLE 7 Weight Percent Ingredient Terbinafine PVP, Benzyl EthanolExample HCl DDAIP•HCl USP Alcohol to 100% 9(A) None None 0.5 0.75 q.s.(control) 9(B) 1 0.5 0.5 0.75 q.s. 9(C) 1 None 0.5 0.75 q.s. 9(D) None0.5 0.5 0.75 q.s. 9(E) None 1 mg/ml None None None in DMSO 9(F) 1 mg/mlin None None None None DMSO 9(G) 1 μg/ml in None None None None DMSO9(H) 1 μg/ml in 1 μg/ml None None None DMSO in DMSO 9(I) ComparativePENLAC ™ Nail Lacquer Solution Topical Solution 8% Note: Ex. 9(I)contains 80 mg ciclopirox in a solution base consisting of ethylacetate, NF; isopropyl alcohol, USP; and butyl monoester ofpoly[methylvinylether/maleic acid] in isopropyl alcohol (DermikLaboratories, Inc.).

MIC assay was determined using the broth dilution procedure described inExample 8 performed in microtiter wells with RPMI 1604 as the diluent.Serial dilutions of each test composition were made in RPMI diluent, andthen 100 μl of undiluted test composition and of each dilutedcomposition was added to a respective microtiter well. Conidialsuspension (100 μl) was then added to each well and the plates wereincubated at an incubation temperature of about 35° C. for an incubationperiod of 4 days dermatophytes, and 48 hours for yeasts. For MFCdetermination, undiluted test composition was added to wells cut intothe agar and allowed to diffuse. The MIC endpoint was the lowestconcentration that inhibited 80% of fungal growth as compared to thegrowth control. The MFC endpoint was the lowest concentration to produce1-2 colonies. The zone of inhibition size was measured (diameter of arearemaining clear, i.e., lacking growth).

The zone of inhibition (diameter size in mm), and the dilution factorsfor the MIC and MFC assays obtained with each of the compositions isshown in Table 7-A.

TABLE 7-A Example Zone size Dilution (Composition: Diluent) No. (mm) MICMFC 9(A) Zero 1:32 1:16 9(B) 80 >1:512 >1:512 9(C) 82 >1:512 >1:512 9(D)Zero 1:64 1:32 9(E) Zero 1:32 1:4  9(F) 80 >1:512 >1:512 9(G) 18 0.03μg/ml 0.125 μg/ml 9(H) 18 0.03 μg/ml 0.125 μg/ml 9(I) 33 >1:512 >1:512

The terbinafine-containing nail coat compositions, Exs. 9(B) and 9(C)were fungicidal at the highest dilution (>1:512). The terbinafine-freecompositions, Exs 9(A) and 9(D) were weakly fungicidal, based on MICassays, but produced no zone of inhibition, indicating that anyinhibitory effect observed was likely attributable primarily to someantimicrobial contribution from the benzyl alcohol and ethanol in thevehicle. The terbinafine-containing compositions were judged about 2.4times as effective as the commercial nail lacquer, Ex. 9(I), atequivalent volume concentrations, based on the zone of inhibition. Thecommercial nail lacquer was comparable to the terbinafine-containingcompositions, based on MIC and MFC assays. Some difficulty wasencountered with the commercial nail lacquer at the highestconcentrations due to evaporation of the lacquer vehicle and hardeningof the lacquer in the microtiter well.

In DMSO solvent, the fungicidal efficacy at a dilution of >1:512 ofterbinafine hydrochloride at 1 mg/ml concentration was again confirmedby Ex. 9(F), with at most some weak efficacy from the penetrationenhancer alone (Ex. 9(E)) based on MIC. At a terbinafine hydrochlorideconcentration of 1 μg/ml, the fungicidal efficacy of the terbinafinehydrochloride was substantially equivalent with or without thepenetration enhancer present (Exs. 9(G), 9(H)).

The foregoing is intended to be illustrative of the present invention,but not limiting. Numerous variations and modifications may be effectedwithout departing from the true spirit and scope of the invention.

1-22. (canceled)
 23. A method for ameliorating or preventing fungalinfection of a toenail or fingernail comprising contacting a fungallysusceptible or infected nail and skin tissue adjacent thereto with anail coat composition consisting essentially of, on a total compositionweight basis: about 0.5 to about 10 weight percent terbinafinehydrochloride: about 0.1 to about 25 weight percentdodecyl-2-(N,N-dimethylamino) isopropionate hydrochloride: about 0.1 toabout 10 weight perecent benzyl alcohol; about 0.1 to about 5 weightpercent polyvinylpyrrolidone; and the remainder ethanol.
 24. The methodaccording to claim 23 wherein the contact is maintained for a period ofat least about 0.5 hours.
 25. The method according to claim 23 whereinthe method is performed at least once a day.
 26. The method according toclaim 24 wherein the method is performed at least once a day.
 27. Themethod according to claim 23, wherein the method is practiced dailyuntil new nail growth is free of fungal infection.
 28. The methodaccording to claim 24, wherein the method is practiced daily until newnail growth is free of fungal infection.
 29. The method according toclaim 23, wherein the composition is applied by brushing or spraying.30. The method according to claim 23, wherein the nail coat compositionconsists essentially of, on a total composition weight basis: about 10weight percent terbinafine hydrochloride: about 0.5 weight percentdodecyl-2-(N,N-dimethylamino) isopropionate hydrochloride: about 0.75weight perecent benzyl alcohol; about 0.5 weight percentpolyvinylpyrrolidone; and the remainder ethanol.